Looking for compatible rails

Hi all just bought my first rack it’s a Vevor 27u 4 post open rack


But the issue having is finding rails that both fit my chassis and also for within the compatible specs for my rack (which is only 23") deep.

The chassis I have is a rose will lab 5400 which is 27" deep and the rails I first attempted to use were tbe official rose-will ones (which had I read the reviews o would have know , commonly don’t fit a lot of racks)

I then stumbled across the server-builds article/forum post about using the ISTAR TC-RAIL rails and that these usually work , but I’m struggling to find any that BOTH support my chassis of 27" deep and also support a rack that’s only 23" deep.

Should I go for the 20" version of the TC-RAIL , the 26"or the 20" version , I really have no clue.

Don’t bit my head off please I’m new to rack-mount stuff and this is my first crack at a he lab.

Thanks in advance.